1. Technical Field
The present disclosure relates to a method for designing three-dimensional freeform surface based on point-by-point construction and iteration process.
2. Description of Related Art
Compared with conventional rotationally symmetric surfaces, freeform optical surfaces have more degrees of freedom, which can reduce the aberrations and simplify the structure of the system in optical design. In recent years, with the development of the advancing manufacture technologies, freeform surfaces have been successfully used in the optical field, such as head-mounted-displays, reflective systems, varifocal panoramic optical systems, and micro-lens arrays.
However, conventional methods only consider the coordinates of the feature data points, but ignore the normal vectors of the feature data points, therefore, the shape of the freeform surfaces designed by conventional methods is inaccurate. Since the refraction and reflection of light are very sensitive to the normal vector of the freeform surfaces, conventional methods also reduce the optical performance of the systems using these freeform surfaces. Additionally, in conventional direct design methods, the freeform surfaces are designed by a direct construction method, the image quality of the freeform surfaces is generally low, and further optimization will be much more difficult.